Fuel injection device



"` June 23, 1942.v w, M, NlcHoLs l FUEL INJECTION DEVICE:

Filed May 15, 1941 amm-5' Patented June 23, 1942 FUEL INJECTION DEVICEwilliam M. Nichols, Auburn, N. Y., assignor to American LocomotiveCompany, New York, N. Y., a corporation of New York Application May 15,1941, Serial No. 393,643

1 Claim.

This invention relates to fuel injection devices the reduced speeds ofthe range is undesirably correspondingly reduced, due to the reducedvelocity of the pump. Also when the engine is running at the higher,speeds of the range, extreme pressure waves are created in the pipebetween the fuel pump and injector nozzle, due to the sudden spill ofthe fuel to terminate injection. These pressure waves have a tendency toopen the nozzle valve, thereby causing a second and perhaps a thirdinjection at a timeundesirable for proper operation of the engine.Furthermore, as the conventional pump, in a single pumping operation, isrequiredto build up the pressure to a point Where the nozzle valve willopen, then to maintain the pressure during injection, and thereafter tospill `the fuel to terminate injection, the period of injection isvcon-Ysequently undesirably long. The elimination of one or more of thesesteps permits a shorter injection period to be obtained.

It is an object of the present invention to provide a fuel injectiondevice which will not' lieve the aforementioned undesirable character`1s ics.

A further object is to provide an improved injector nozzle.

A further object is to provide a fuel injection device in which twoseparate fluid pumps coact toI effect injection, one pump providing fuelto the injector nozzle, and the other providing a .fluid for actuatingthe. nozzle valve.

Other and further objects of this invention lwill appear from thefollowing description, the accompanying drawing and the appended claim.

Referred to the drawing forming a part of the present application,Figure 1 is a diagrammatic view in vertical central section illustratingone embodiment of the fuel injection device of the present invention,parts being shown in full and other parts broken away; Fig. 2 is adiagramwhen fuel is delivered to the nozzle, provided the.

invention, parts being brokenaway; and Fig. 3 is a diagrammatic planview of an internal combustion engine, showing the arrangement of thefuel injection devices therefor of the type illustrated in Fig. 1. y

Referring to Fig. 1, the fuel injection device, indicated generally bythe reference numeral I, includes an injector nozzle 2, a fuel pump 3connected to the nozzle by a pipe 4, and a smaller valve-actuating fluidpump 5 connected to the nozzle by a pipe 6.

The fuel pump 3 is illustrated as of the plunger type, although othertypes of pumps may be em-y ployed if desired. Similar remarks apply topump 5, but the following description will be limited to the type ofpump shown, as it has been found that this type is especially welladapted to the present invention.

Pump 3 includes a body 1 having a cylinder a cap 9 therefor, fuel inletpipe I0, fuel discharge passage I I, plunger I2 and check valve I3. Pump5 similarly includes a body I4 having a cylinder I5, cap I6 therefor,fluid inlet pipe I1, uid discharge passage I8, plunger I9 and checkvalve 20. I

Pump 3 controls the period .duringwhich fuel is delivered to the nozzle2. Pump 5 controls the period during which the nozzle valve (later to bedescribed) is maintained in open position. In-

`jection may commence when the nozzle valve is l opened, provided fuelunder pressure has already been delivered to' the nozzle, or it maycommence nozzle valve is already open. Similarly injection may beterminated by the closing of the nozzle 4 valve or by pump 3 terminatingdelivery of fuel to the nozzle. e

It has been found preferable to operate the pumps so that pump 3 beginsto pump before and continues to pump after pump 5, so that a constantsupply of fuel under'pressure is available during the periodin which thenozzle valve is kept open by pump 5. Thus pump 5 determines thebeginning and the end of injection. This insures a quick commencement ofinjection and a quick termination, avoiding dribbling of fuel into theengine cylinder at the beginning and lend of injection, which dribblingeffects poor combustion `in the cylinder. This is an added advantage ofthe present invention.

Where,.as in the present case, the commencement and termination ofinjection are controlled by` the pump 5, Vpump 5 must be adjustable ,topermit the engine to run at different speeds.

matic view, in elevation, of a modification of the 5.5 Adjustable pumps4are well known and for this f reason pump has been shown more or lessdiaadjusted to change the speed of the engine.

grammatically in Fig. 1, no detailed description of an adjustable pumpbeing deemed necessary. An adjustable pump which may be employed to dothe work of pump 5 is shown in patent to Baur, 1,871,872, dated August16, 1932.

Fuel pump 3 may be adjustable or not, depending upon the manner in whichit is employed. When an adjustable fuel pump is to be employed, it maybe similar to the pump of the above mentioned patent. While, as stated,the pumps are shown diagrammatically, it will be noted, however, thatthe metering groove of the patent which is responsible for theadjustability, is indicated on each of the plungers I9 and I2 of thepumps 5 and 3. Obviously, when pump 5 controls the commencement andtermination of injection, pump 3 need merely supply enough fuel tonozzle 2 so that fuel under pressure will be available during the timethe nozzle valve is in open position. g If a by-pass is provided toprevent undesirable pressures at certain speeds, a pump 3 can beutilized which is not adjustable. However, it has been found that a pump3 which is adjustable similar to pump 5 works very well, the adjustmentof pumps 3 and 5 bearing a relation to each other so that they can besimultaneously In a similar manner, if commencement and termination ofinjection are to be controlled by pump 3, then it would necessarily bepump 3 which would be adjustable, and a non-adjustable pump 5 could beemployed.

As pump 5 need only supply uid for opening the nozzle valve, itsdelivery need not be as large as the delivery of the conventional fuelpump. It is-therefore possible to get more accurate adjustments andquicker responses in pump 5 in order to actuate the nozzle valve than ispossible in a conventional fuel pump which operates to both inject fueland actuate the nozzle valve. This is an added advantage `of the presentinvention.

Pumps k3 and 5' may be operated from a common cam shaft (not shown) andin such case they would be on the same side of the internal combustionengine, indicated generally by the reference numeral 2| (Fig. `3).However, it has been found desirable to employ separate cam shafts forpumps 3 and 5. These cam shafts can be arrangedend to end so that thearrangement of the pumps can be the same as when a single cam shaft isemployed. The purpose of employing separate cam shafts is to provide foradjustment of one relative to the other in order that the relativeaction of the plungers of pumps 3 and 5 can be predetermined. Ordinarilythe plunger I2 of pump 3 will start its stroke before the plunger I9 ofpump 5 and the cam shafts will be so adjusted, the cam. shaft for pumps5 being adjustable and the cam shaft for pumps 3 being fixed.

Nozzle 2 is disposed over the center of the engine cylinder 22 intowhich it injects fuel, and is supported by the cylinder head in itsvertical position shown in Fig. 1. Nozzle 2 includes a casing 23 whichhas a fuel receiving part or chamber 24 which is connected to pipe 4 byan inlet port 25 and which opens into the engine cylinder 22 by means ofa passage or injection port 26 and jets 21. A valve seat 28 is formedaround the chamber end of passage 28 and a nozzle valve 29, forming apart of a valve element 30, normally engages this seat, closing passage28.

Casing 23 further has a. valve-actuating fluid chamber 3| which isconnected to pipe 6 by an inlet port 32. A cylinder 33, of a smallerdiameter than the chamber 3l, opens at one end into chamber 3| and apiston 34 is disposed in the nozzle cylinder. Piston 34 is connected tonozzle valve 29 by a valve stem 35 which extends through chamber 3| andthrough a guide-forming passage 36 extending from chamber 3| to chamber24. The valve stern 35 fits in close sliding engagement in the guide,preventing passage of fluid from one chamber to the other chamber.However, if the fluid pumped by pump 5 is fuel oil,'then obviouslyintermingling of the contents of the chambers will be immaterial.

Casing 23 further has a chamber 31 in which is disposed an energizedspring 38. In the drawing the casing is shown formed of two parts,namely a body 39 and a hollow cap 40, the cap providing chamber 31 andbeing secured to the body by threads 4I'. The spring presses at one endagainst the cap and at the other end against a seat 42 which issupported on a projection 43 formed integrally with the piston 34, theprojection, piston, valve stem and nozzle valve all being integral partsof the valve element. Thus spring 38 holds the nozzle valve 29 againstseat 28, normally closing passage 26, and returns nozzle valve 29 tothis position after it has been raised by fluid from pump 5. A stop 44is provided in the cap limiting the lifting of the valve element. Whilethe pump 5 has been described as adapted Ato open the nozzle valve andthe spring 38 'to close it, it will be understood that The particularconstruction lof nozzle 2 showinl and described is by way ofillustration only, and

various other suitable designs may be employed.

All such various types of nozzles are contemplated as within the scopeof the present invention.

Valve stem 35 is of a smaller diameter than piston 34, thereby providinga shoulder or piston head 45 against which the valve-actuating fluidoperates.

As pump 5 operates to merely push the piston upward., thevalve-actuating fluid.I may be a fluid which is trapped between the pumpplunger I9v and the piston 34. However, as considerable heat isgenerated in the valve-actuating fluid, it is contemplated bleeding offa small amount of fluid through a bleeder port 48 formed in the chamber3| for each operation of the plunger I9. `.This fluid is replaced byfluid entering cylinder |5 through pipe I'I. The fluid which passesthrough port 48 is returned to the source of supply by pipe 41.

One of the Ways of operating the fuel injection device of Fig. 1 is asfollows: Fuel under pressure is pumped to chamber 24 by pump 3 and fluidunder pressure is pumped to chamber 3| by pump 5. When the pressure inchamber 3| is sufficient to overcome the resistance of spring 38, thenozzle valve 29 is lifted off the seat 28, and, due to the operation ofplunger I2, the fuel is injected into the engine cylinder. As the fuelwill be at a high pressure in chamber 24 before nozzle valve 29 islifted, injection will commence very quickly, vinsuring the injection ofproperly sprayed fuel and eliminating the dribbling in of poorly sprayedfuel, which dribbling often occurs when the nozzle valve is opened bythe fuel under pressure. When plunger I9 has reached the end of th'edelivery portion of its `the delivery portion of its stroke.-

lstroke the pressure in chamber Il is dropped and spring 39 quicklyreturns piston 34 which effects rapid` closing of nozzle valve 29. Fuelis-being 'injected into the engine cylinder in 'properly sprayedcondition'up to the moment nozzle valve 29 closes, as plunger I2 isstill on bling is prevented at termination of injection. The harmfuleffects of dribbling are well known and no further comment is deemednecessary. `Suffice it to say that if poorly sprayed fuel enters thecylinder, then poor combustion results. Pump 9 visadapted to supply fuelproperly to the engine at low speeds as well as at high speeds, for-although at low speeds the pump plunger has a reduced velocity,thiswis,(minnen-V sated for by the fact that the pump canpump a largesupplyv of fuel under pressure, no part of the plunger stroke beingneeded for other' steps. Thus at reduced speeds, when the nozzle valve29 is raised, the fuel .in vchamber 24 is r under suitable pressure toproperly spray it,

duced thereby in pipe I may be provided for,

taking into account the relativesize of piston 34 and strengthof spring9|, such that there will be no pressure waves produced in pipe 9 yof amagnitude sufficient to operate the valve.

There is an injection device I for eachcylin- Y der of the engine, asshown in Fig. 3. However, as pump 3 functions only to supply fuel under.pressure to chamber. 24, it is not necessary that there be a pump l foreach cylinder. Thus, in Fig. 2 a modication is shown in which `a singlepump 3 provides fuel to a plurality of injector nozzles 2'., all thepipes 4' branching from a single supply or pipe 49. 'I'he pump 3' isshown similar to pump 3. However, as it must pumpmore fuel than pump 3,it should be larger in order to maintain a pressure in pipe 49 suitablefor injection, or if desired it can be given Thus dribmorereciprocations engine crankshaft rev-A olution. That is'I to sa pipe 49acts as a reservoir for. fuel under pressure so that a supply is alwaysavailable, check valve I3' preventing` backward flow of fuel throughpipe 49. Pump 9' may take care of several injector nozzles, dependingupon its pumping capacity. Thus, for instance, in a six-cylinder engine,there might be three pumps 3' instead of six, as in the embodiment ofFig. 1.

While there have been hereinbefore described approved embodiments ofthis invention. it will be understood that many and various changes andmodifications in form, arrangement of'parts andy details of constructionmay be made thereto without departing from the spirit vof the invernntion, and that all such changes andmodications as fall within the scopeof theappended claim are tion.

The invention claimed and desired to be se- Y 'cured by Letters Patentis:

Fuel injection apparatus for supplying fuel to an internal combustionengine cylinder comprising acasing having a fuel injection port in oneend thereof provided' with a valve seat,1ra

fuel chamber adjacent said seat, a piston cylinder, and' a wallseparating said chamber from said cylinder having an orifice extendingtherethrough: a unitary valve element including a control valve for saidseat, a piston .in said cylinder spaced from said wall providing a`chamber for working fluid, and a stem extending through and closing saidorifice and rigidly connecting said .valve with said piston: apumpingdevice communicating with said fuel chamber for supply of fuel thereto;another pumping device communicating with said working fluid chamber forsupplying working fluid thereto and for alternately producing fluidpressure and release of same therein whereby under said pressure 'saidpiston vis moved in one direction to move said valve to port-openposition; and a spring bearing on said piston for moving said' piston inthe opposite direction when said pressure is released for moving saidvalve to portclosed position, said spring being compressed by saidpiston during its first said movement.

WILLIAM M. NICHOLS. v

contemplated as a part of this inven-

